This book provides a unique multi- and interdisciplinary approach to energy conversion technologies by shedding light on the topic from both technological and ethical perspectives. It applies these concepts to examples of engineering problems related to energy conversion – an internal combustion engine and a fuel cell – in order to give the reader a clear idea of how to implement the approaches and do the work. The first part is an introduction to thermodynamics, which is an important concept for engineers when describing and analyzing energy conversion processes in terms of their efficiency. The book goes on to discuss the concepts of energy analysis and life cycle assessment while taking environmental aspects into account, particularly the formation of pollutants. The second part introduces the ethical terminology and describes global and environmental risks associated with energy conversion, as well as aspects of sustainability. The book is based on an introductory lecture on energy technologies for undergraduate engineering students. However, the explanation of the various concepts remains illustrative, avoiding a more complex mathematical or philosophical treatment of the subject. Therefore, this book provides a modern but timeless introduction to energy conversion technologies that is well suited for the generally interested reader.